Two boats simultaneously departed from the pier in the same direction. Speed of 1 boat is 35 km / h, speed of 2 boats is 50 km / h.

Two boats simultaneously departed from the pier in the same direction. Speed of 1 boat is 35 km / h, speed of 2 boats is 50 km / h. How long will it take between boats 30 km?

According to the condition of the problem, the boats left at the same time, therefore they will move the same amount of time.
Let’s say the distance between the boats is 30 km after they have been on the way for x hours.
During this time, the first boat will pass 35 * x (km), and the second boat, respectively – 50 * x (km).
Since the boats are moving in one direction, we get the following equation:
50 * x – 35 * x = 30,
15 * x = 30,
x = 30: 15,
x = 2.
Answer: in 2 hours.